1. Field of the Invention
The present invention relates an improvement in a disc transfer apparatus which relies on a spring force for inserting a disc and on a motor for removing the disc.
2. Description of the Related Art
Generally, in a disc transfer apparatus, it is desired to rapidly insert a disc but relatively slowly remove the disc to prevent the disc from rushing out. Laid-open Japanese Patent Application No. 11-86401 shows a disc transfer apparatus which comprises a spring-based toggle mechanism in a disc transfer unit such that a disc is rapidly inserted with the spring force of the toggle mechanism while the disc is removed relatively slowly with the power of a motor.
Specifically, a push-back member is coupled with a push-in member, and the push-back member is urged by the toggle mechanism to be pivotally moved in two opposite directions from a neutral position defined and limited by the toggle mechanism. When a disc is inserted, the push-back member is pushed by the disc for insertion. As the push-back member and goes beyond the neutral position defined by the toggle mechanism, the push-in member is triggered and follows the push-back mechanism to push the disc into a playing position with a spring force. In this event, if a motor acts as a load during the insertion of the disc, the disc cannot be lightly inserted. As such, a power transmission path from the motor to the push-back member is cut off when the disc is inserted to lightly insert the disc. On the other hand, a disc removal operation causes the motor to start to connect the power transmission path by a rotating force of the motor to pivotally move the push-back member to push back the disc.
The disclosed apparatus employs a dedicated disc transfer motor which is driven only in a xe2x80x9cdisc removal operation.xe2x80x9d Therefore, if the motor is driven other than the disc removal operation, the power transmission path will be unintentionally connected by the rotating force of the motor, which causes the push-back member to push back the disk. In other words, the disc player disclosed in Laid-open Japanese Patent Application No. 11-86401 experiences trouble in that if the disc transfer motor is used as a motor for moving a pickup (for simplifying the structure of the apparatus and reducing the manufacturing cost), the power transmission path is unintentionally connected from the motor to the push-back member when the pickup is to be moved. Therefore, a disc is pushed back by the push-back member during a playback operation.
The present invention has been made to solve the problem as mentioned above, and it is an object of the invention to provide a disc transfer apparatus which relies on a spring force to insert a disc, and on a motor for moving a pickup thereby removing the disc. Accordingly, the structure is simplified and the manufacturing cost of the disc transfer apparatus is reduced.
A disc transfer apparatus according to the present invention couples a push-back member with a push-in member such that the push-back member is pivoted in one direction to push back a disc and the push-in member pushes the disc into a playing position following the pivotal movement of the push-back member in the other direction. A toggle mechanism is also provided for urging the push-back member for bi-directional pivotal movements. The power of a two way motor in one direction is transmitted to the push-back member through a transmission mechanism.
The transmission mechanism includes a control gear, and an upstream gear and a downstream gear in mesh with the control gear upstream and downstream of a power transmission path, respectively. When the push-back member is pivoted in the opposite direction, the control gear is held without meshing with the upstream gear and the downstream gear so as to insert the disc is inserted with a spring force. When the disc is removed, the control gear is released from the holding mechanism by ejecting means and brought into mesh with the upstream gear and the downstream gear so as to remove the disc by the power of the motor.
When the control gear is comprised of two coaxially integrated toothless gears, and these toothless gears are simultaneously placed opposite to the upstream and downstream gears, respectively, the structure of the apparatus can be simplified.
The structure can be further simplified by forming the push-back member with an angle cam to which a cam follower is resiliently pressed to provide the toggle mechanism, and selectively positioning the cam follower on one of the inclines of the angle cam from its peak to urge the push-back member for bidirectional pivotal movements.
Alternatively, a toggle spring may be extended between the push-back member and a floating chassis to constitute the toggle mechanism to further simplify the structure.
In the apparatus, to control movement of a chucking mechanism into contact with and away from a turntable by a cam member which is reciprocally movably associated with the pivotal movements of the push-back member, the cam member is provided with a plurality of steps on a cam face such that the chucking mechanism is moved step by step into contact with and away from a turntable to prevent shock in a chucking operation.
Further, when a sliding mechanism is interposed in the power transmission path for absorbing an overload, the sliding mechanism generates slippage to absorb the overload even if the removal of a disc is forcedly stopped, which prevents the motor from moving the pickup or the like from damaging.